Method for displaying 3d image and device for same

ABSTRACT

Provided is a device including a camera configured to capture an image of eyes of a user who is watching three-dimensional (3D) video; and a processor configured to obtain an eye feature of the user from the captured image of the eyes of the user, determine a degree of eyestrain degree of the user based on the obtained eye feature, and adjust a parallax of the 3D video according to the degree of eyestrain of the user.

PRIORITY

This application is a National Phase Entry of PCT InternationalApplication No. PCT/KR2015/013992, which was filed on Dec. 21, 2015, andclaims priority to Chinese Patent Application No. 201510385882.2, whichwas filed on Jun. 30, 2015, and to Korean Patent Application No.10-2015-0177368, which was filed on Dec. 11, 2015, the contents of eachof which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a three-dimensional (3D) displaytechnology, and more particularly, to a device and method of adjusting a3D display effect.

BACKGROUND ART

As electronic technology and three-dimensional (3D) display technologyrapidly develop, a variety of electronic devices that support 3D videoreproduction are used in daily life. Accordingly, users can view a 3Dvideo without needing to go to movie theatres. In addition, astereoscopic depth effect of such 3D video provides users with anenhanced visual experience. At present, research into 3D displaytechnology has become more widespread in the display field.

The principle of 3D display technology is to achieve binocular parallaxby providing two slightly different images to left and right eyes,respectively, thereby producing a 3D stereoscopic effect in the brain.For example, the position of a first object 10 in a left eye picture maybe different from that of a first object 20 within a right eye picture.Throughout this specification, a left eye picture may refer to a pictureprovided to the left eye, and a right eye picture may refer to a pictureprovided to the right eye.

The parallax may refer to a difference between the positions of the sameobject in left and right eye pictures. In other words, the parallax mayrefer to a difference between a position of an object on the left retinaand a position of the same object on the right retina. For example, whenan image of an object is made incident at a distance of 4 mm from thefovea of the left eye and an image of the same object is made incidentat a distance of 3 mm from the fovea of the right eye, the parallax ofthe object may be 1 mm. The parallax may also refer to a differencebetween a position of an object on the left eye picture and a positionof the same object on the right eye picture.

In a stereoscopic display system based on a display screen, the largerthe parallax is, the more distinct the out-of-screen and in-screeneffect of the object. The out-of-screen effect may refer to astereoscopic effect in which an object appears to protrude out from ascreen, and the in-screen effect may refer to a stereoscopic effect inwhich an object appears to enter into a screen.

In detail, according to the difference between the positions of the sameobject on the screen in left and right eye pictures, the parallax may bedivided into a negative parallax, a positive parallax, and a zeroparallax.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

The present invention provides an apparatus and method for adjusting aparallax in three-dimensional (3D) video, based on a degree of eyestrainof a user.

DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B and 1C illustrate respective examples of a negativeparallax, a positive parallax, and a zero parallax in three-dimensional(3D) display technology.

FIG. 2 is a diagram illustrating adjusting of a 3D display effectaccording to a current degree of eyestrain of a user according to anembodiment of the present disclosure.

FIG. 3 is a block diagram of a device according to an embodiment of thepresent disclosure.

FIG. 4 illustrates a flowchart of a method of adjusting a 3D displayeffect, according to an embodiment of the present disclosure.

FIG. 5 illustrates a flowchart of a method of adjusting a 3D displayeffect, according to another embodiment of the present disclosure.

FIGS. 6A and 6B illustrates an example of adjusting a parallaxparameter, according to an embodiment of the present disclosure.

FIG. 7 illustrates a flowchart of a method of adjusting a 3D displayeffect, according to another embodiment of the present disclosure.

FIGS. 8A and 8B illustrates an example of adjusting a parallaxparameter, according to another embodiment of the present disclosure.

FIGS. 9A, 9B and 9C illustrates an example of adjusting a parallaxparameter based on a human eye focusing characteristic when changing ascene, according to an embodiment of the present disclosure.

FIG. 10 illustrates a flowchart of a method of adjusting a 3D displayeffect, according to another embodiment of the present disclosure.

FIG. 11 illustrates a user interface for adjusting a 3D display effect,according to an embodiment of the present disclosure.

FIG. 12 is a block diagram of a device according to an embodiment of thepresent disclosure.

FIG. 13 is a block diagram of a device according to another embodimentof the present disclosure.

BEST MODE

According to an aspect of the present invention, there is provided adevice including a camera configured to capture an image of eyes of auser who is watching three-dimensional (3D) video; and a processorconfigured to obtain an eye feature of the user from the captured imageof the eyes of the user, determine a degree of eyestrain degree of theuser based on the obtained eye feature, and adjust a parallax of the 3Dvideo according to the degree of eyestrain of the user.

The processor may adjust the parallax of the 3D video by adjusting atleast one of a mean parallax between a left eye image and a right eyeimage of the 3D video, a maximum value of a negative parallax betweenthe left and right eye images, a maximum value of a positive parallaxbetween the left and right eye images, and a parallax range that is adifference between the maximum value of the negative parallax and themaximum value of the positive parallax.

The eye feature of the user may include at least one of a blinkingfrequency, an eye-closed time, a change in binocular focus points, and abinocular convergence angle.

When the determined degree of eyestrain of the user is equal to orgreater than a first threshold, the processor may adjust the parallax ofthe 3D video.

The processor may determine whether the parallax of the 3D video isequal to or greater than a second threshold, and, when the parallax ofthe 3D video is equal to or greater than the second threshold, theprocessor may adjust the parallax of the 3D video to be less than thesecond threshold.

The processor may adjust the parallax of the 3D video by adjusting achange rate of a parallax between frames of the 3D video.

The processor may determine a difference between parallaxes of an n-thframe and an (n−1)th frame of the 3D video, and, when the differencebetween the parallaxes is equal to or greater than a third threshold,the processor may adjust the parallax of the n-th frame such that thedifference between the parallaxes is less than the third threshold, tothereby adjust the change rate of the parallax between the frames of the3D video.

The processor may increase the parallax of the n-th frame such that thedifference between the parallaxes is less than the third threshold, tothereby adjust the change rate of the parallax between the frames of the3D video.

The device may further include an output interface, wherein theprocessor may control the output interface to output, to the user, aparallax-adjusted 3D video obtained by adjusting the parallax of the 3Dvideo.

The device may display, on the output interface, a notification windowindicating that the parallax of the 3D video has been adjusted.

According to another aspect of the present invention, there is provideda method of adjusting a 3D display effect includes capturing an image ofeyes of a user who is watching 3D video; obtaining an eye feature of theuser from an image of the captured image of the eyes of the user;determining a degree of eyestrain of the user, based on the obtained eyefeature; and adjusting a parallax of the 3D video according to thedegree of eyestrain of the user.

The adjusting of the parallax of the 3D video according to the degree ofeyestrain of the user may include adjusting at least one of a meanparallax between a left eye image and a right eye image of the 3D video,a maximum value of a negative parallax between the left and right eyeimages, a maximum value of a positive parallax between the left andright eye images, and a parallax range that is a difference between themaximum value of the negative parallax and the maximum value of thepositive parallax.

The adjusting of the parallax of the 3D video according to the degree ofeyestrain of the user may include, when the determined degree ofeyestrain of the user is equal to or greater than a first threshold,adjusting the parallax of the 3D video.

The adjusting of the parallax of the 3D video according to the degree ofeyestrain of the user may include determining whether the parallax ofthe 3D video is equal to or greater than a second threshold, and, whenthe parallax of the 3D video is equal to or greater than the secondthreshold, adjusting the parallax of the 3D video to be less than thesecond threshold.

The adjusting of the parallax of the 3D video according to the degree ofeyestrain of the user may include adjusting the parallax of the 3D videoby adjusting a change rate of a parallax between frames of the 3D video.

The adjusting of the parallax of the 3D video by adjusting the changerate of the parallax between frames of the 3D video may includedetermining a difference between parallaxes of an n-th frame and an(n−1)th frame of the 3D video, and, when the difference between theparallaxes is equal to or greater than a third threshold, adjusting theparallax of the n-th frame such that the difference between theparallaxes is less than the third threshold, to thereby adjust thechange rate of the parallax between the frames of the 3D video.

The adjusting of the parallax of the n-th frame such that the differencebetween the parallaxes is less than the third threshold may includeincreasing the parallax of the n-th frame such that the differencebetween the parallaxes is less than the third threshold, to therebyadjust the change rate of the parallax between the frames of the 3Dvideo.

The method may further include outputting, to the user, aparallax-adjusted 3D video obtained by adjusting the parallax of the 3Dvideo.

The method may further include displaying a notification windowindicating that the parallax of the 3D video has been adjusted.

MODE OF THE INVENTION

Hereinafter, the terms used in the specification will be brieflydescribed, and then the present invention will be described in detail.

Although general terms widely used at present were selected fordescribing the present invention in consideration of the functionsthereof, these general terms may vary according to intentions of one ofordinary skill in the art, case precedents, the advent of newtechnologies, and the like. Terms arbitrarily selected by the applicantof the present invention may also be used in a specific case. In thiscase, their meanings need to be given in the detailed description of theinvention. Hence, the terms must be defined based on their meanings andthe contents of the entire specification, not by simply stating theterms.

The terms “comprises” and/or “comprising” or “includes” and/or“including” when used in this specification, specify the presence ofstated elements, but do not preclude the presence or addition of one ormore other elements. The terms “ . . . unit” and “ . . . module” whenused in this specification refers to a unit in which at least onefunction or In operation is performed, and may be implemented ashardware, software, or a combination of hardware and software.

Embodiments of the present invention are described in detail herein withreference to the accompanying drawings so that this disclosure may beeasily performed by one of ordinary skill in the art to which thepresent invention pertain. The present disclosure may, however, beembodied in many different forms and should not be construed as beinglimited to the embodiments set forth herein. In the drawings, partsirrelevant to the description are omitted for simplicity of explanation,and like numbers refer to like elements throughout.

In the related art, according to a method of improving the comfort levelof the eyes of a user by reducing the parallax of an object, when a userviews a 3D video, a satisfactory 3D stereoscopic display effect may becaused due to the improvement of the comfort. However, the effect of apicture may become similar to 2D display.

To address this problem, according to some embodiments of the presentdisclosure, when a user views a 3D video, a parallax parameter of the 3Dvideo may be adjusted according to the current degree of eyestrain ofthe user. By adjusting the parallax parameter of the 3D video accordingto the current degree of eyestrain of the user, a stereoscopic displayeffect of the 3D video may be maximized while reducing the eyestrain ofthe user.

FIGS. 1A, 1B and 1C illustrates respective examples of a negativeparallax, a positive parallax, and a zero parallax in 3D displaytechnology. As shown in FIG. 1A, an object 40 may have a negativeparallax, and a user may feel like the object 40 with a negativeparallax is located in front of a screen. As shown in FIG. 1B, theobject 40 may have a positive parallax, and the user may feel like theobject 40 with a positive parallax is located behind the screen. Asshown in FIG. 1C, the object 40 may have a zero parallax, and the usermay feel like the object 40 with a zero parallax is displayed on thescreen, that is, the object 40 is displayed with a traditional 2Ddisplay effect without any perceptual depth effect from a picture. Ingeneral, compared with the positive parallax, the negative parallax mayprovide a more distinct stereoscopic effect. In the case of either apositive parallax or a negative parallax, a stereoscopic effectcorresponding to a larger parallax value is more distinct than that of asmaller parallax value.

The larger the parallax is, the stronger the depth perception of whichthe user can feel is. However, a larger parallax causes discomfort andeyestrain of the user, and thus it is easy to increase the burden of theeyes of the user. According to Panum's laws, the eyes of a user havelimited capability with respect to merging two pictures with parallaxinto one picture. In other words, when the parallax is larger than acertain value, the user may see two pictures rather than one picture.From another aspect, when viewing an object, two eyes of the user shouldfocus on the object so that the user can combine different images seenby the two eyes into one stereoscopic image through a fusion function ofhis or her brain. An angle formed between lines of sight from the twoeyes to a focus point 30 may be called a convergence angle.

As shown in FIGS. 1A and 1B, the object 40 with a negative parallaxshown in FIG. 1A has a larger convergence angle compared with the object40 with a positive parallax shown in FIG. 1B. In physiology, it is easyto cause eyestrain when viewing an object with a large convergence angle(that is, when viewing the object at a near distance). Accordingly,compared with an object with a positive parallax, an object with anegative parallax has an enhanced stereoscopic effect, but may causeeyestrain more easily.

Generally, in the related art, a processing technology of reducing theparallax of an object in a stereoscopic video is designed such that boththe positive parallax and the negative parallax are limited within acertain range. The parallax being reduced may mean being closer to azero parallax so as to form a smaller convergence angle, which causesthe effect of the picture to seem more like a 2D playback. Accordingly,although the comfort level of the eyes is improved, the 3D stereoscopicdisplay effect of the picture may be sacrificed. The reduction in the 3Dstereoscopic display effect of the picture may cause the effect of thepicture to seem more like a 2D playback. For this reason, the user'sstereoscopic feeling will be greatly degraded when the stereoscopicviewing comfort level is improved by reducing the parallax.

In addition, a large parallax or large convergence angle within acertain range may not have an immediate influence on the eyestrain andthe comfort level. Likewise, the user may feel uncomfortable in his orher eyes only after watching a book or a computer display for a longtime. Accordingly, even when a 3D playback of the same parallax isperformed, the degree of fatigue felt by the user may vary depending ona watching time period or an eye state of the user.

In conclusion, in an existing scheme for adjusting a 3D stereoscopicdisplay effect, the stereoscopic display effect of a 3D video cannot beguaranteed while ensuring the healthy use of the eyes of a user.

FIG. 2 is a diagram of adjusting a 3D display effect according to acurrent degree of eyestrain of a user according to an embodiment of thepresent disclosure.

As illustrated in FIG. 2, for example, when a 3D video 230 is beingviewed by a user, a head image of the user may be captured by an imagecapturing device 210 (e.g., a camera), and a face recognition may beperformed based on a computer vision library (e.g., an Opencv library),so as to parse an eye image 220 of the user. An eye feature of the usermay be obtained from the eye image 220 of the user. After the eyefeature is obtained, a current degree of eyestrain of the user may bedetermined based on the obtained eye feature, and a parallax parameterof the 3D video 230 may be adjusted based on the current degree ofeyestrain of the user. Accordingly, the comfort level may be improvedwhen viewing the 3D video 230. In this way, the 3D display effect may beautomatically adjusted based on the current degree of eyestrain of theuser. Therefore, the 3D display effect may be ensured, and at the sametime a discomfort in the eyes of the user caused when viewing the 3Dvideo 230 may be effectively reduced.

FIG. 3 is a block diagram of a device 1000 according to an embodiment ofthe present disclosure.

Referring to FIG. 3, the device 1000 may include an eye feature obtainer60, an eyestrain degree determiner 70, and a parallax adjustor 80. Thecomponents of the device 1000 may be accomplished by an image sensor forperforming a specific function, a general-purpose hardware processersuch as a digital signal processor (DSP) and a field programmable gatearray (FPGA), or a special-purpose hardware processor such as adedicated chip, or may be completely accomplished as software through acomputer program, such as, individual modules in an application foradjusting a 3D display effect that is installed in the device 1000.

The eye feature obtainer 60, the eyestrain degree determiner 70, and theparallax adjustor 80 may be accomplished by executing software, such asa computer program, by using hardware. In this case, the eye featureobtainer 60, the eyestrain degree determiner 70, and the parallaxadjustor 80 may be realized as a single controller (not shown).Alternatively, the eye feature obtainer 60 and the eyestrain degreedeterminer 70 may be realized as a single controller (not shown), andthe parallax adjustor 80 may be realized as a separate image processor(not shown). In the device 1000, the eye feature obtainer 60 is used toobtain an eye feature of a user when the user is viewing a 3D video.

In detail, the eye feature obtainer 60 may control an image capturingdevice to capture a head image of the user when the user is viewing a 3Dvideo, and, after the head image of the user is obtained, may perform aface recognition on the head image of the user based on a computervision library so as to parse an eye image of the user from a recognizedface region. The eye feature obtainer 60 may extract an eye feature ofthe user from the obtained eye image.

For example, the eye feature obtainer 60 may extract, from the capturedeye image of the user when the user is viewing the 3D video, at leastone of a blinking frequency, an eye-closed time, a change in binocularfocus points, and a binocular convergence angle as the eye feature.

The eyestrain degree determiner 70 may determine a current degree ofeyestrain of the user according to the obtained eye feature. Forexample, the degree of eyestrain may be a value representing a currentdegree of eyestrain of the user that is dynamically determined based onthe obtained eye feature.

For example, as the number of times the eyes blink per unit timeincreases, the eyestrain degree determiner 70 may determine that thecurrent degree of eyestrain of the user is high.

For example, as the time during which the user is closing his or hereyes increases, the eyestrain degree determiner 70 may determine thatthe current degree of eyestrain of the user is high.

For example, when the eye feature obtained by the eye feature obtainer60 is a change in binocular focus points of the user, the eyestraindegree determiner 70 may synthetically analyze a value representing acurrent degree of eyestrain of the user, based on the change in thebinocular focus points of the user. For example, the eyestrain degreedeterminer 70 may determine that the current degree of eyestrain of theuser is high, when a change in binocular focus points per unit time isfrequent.

For example, when the binocular convergence angle is equal to or greaterthan a critical value, as the binocular convergence angle increases, theeyestrain degree determiner 70 may determine that the current degree ofeyestrain of the user is high.

The parallax adjustor 80 may adjust a parallax parameter of the 3D videoaccording to the current degree of eyestrain of the user. The parallaxparameter may refer to a mean parallax of each pixel pair between a lefteye image and a right eye image of the 3D video, a maximum value of anegative parallax of the pixel pair therebetween, a maximum value of apositive parallax of the pixel pair therebetween, or a parallax range ofthe pixel pair therebetween. As described above, the parallax may referto a difference between the positions of the same object in left andright eye images.

Accordingly, in order to obtain the parallax parameter of the 3D video,an image matching method in which a pixel corresponding to, namely,matched with, each pixel in the left eye image is detected from theright eye image and a parallax between two matched pixels (i.e., adifference of displacement) is obtained may be executed. A pixel in theleft eye image and a pixel in the right eye image corresponding to thepixel in the left eye image may mean a pixel in the left eye image and apixel in the right eye image both representing a single point within thesame object.

As the parallax of each pixel in the 3D video is obtained, a meanparallax of the 3D video or a parallax range comprised of a maximumparallax and a minimum parallax may be obtained. By adjusting the meanparallax or the parallax range, the user's eyestrain may be degraded.The mean parallax may refer to a mean of parallax between matchedpixels, and the parallax range may refer to a difference between maximumvalues of a positive parallax and a negative parallax from among theparallax between matched pixels.

In detail, after the current degree of eyestrain of the user isdetermined by the eyestrain degree determiner 70, the parallax adjustor80 may determine whether the current degree of eyestrain of the user isequal to or greater than an eyestrain threshold. The eyestrain thresholdmay be a preset critical value used to determine whether the userexperiences eye fatigue. For example, by comparing the current degree ofeyestrain of the user with the eyestrain threshold, it may be determinedwhether a 3D display effect should be adjusted. For example, when thecurrent degree of eyestrain of the user is less than the eyestrainthreshold, the parallax adjustor 80 may not adjust the parallaxparameter of the 3D video.

On the other hand, when the current degree of eyestrain of the user isequal to or greater than the eyestrain threshold, the parallax adjustor80 may adjust the parallax parameter of the 3D video in an appropriateway. For example, when the current degree of eyestrain of the user isequal to or greater than the eyestrain threshold, the parallax adjustor80 may determine whether the parallax parameter of the 3D video is equalto or greater than a parallax parameter threshold. When the parallaxparameter is equal to or greater than the parallax parameter threshold,the parallax adjustor 80 may adjust the parallax parameter of the 3Dvideo to be within the parallax parameter threshold. The parallaxparameter threshold may be previously determined, or dynamicallydetermined according to the current degree of eyestrain of the user.

For example, the parallax parameter threshold may be a predeterminedmean parallax, a predetermined parallax range, or a predetermined uniquemean parallax, or may be a parallax range corresponding to the currentdegree of eyestrain of the user. In detail, an appropriate parallaxparameter adjustment function p=ƒ (t, d) may be selected according to apreset condition, and the parallax parameter may be adjusted to bewithin the parallax parameter threshold according to the parallaxparameter adjustment function p=ƒ (t, d), in which p may refer to aparallax parameter of the 3D video after being adjusted, t may refer tothe current degree of eyestrain of the user, and d may refer to aparallax parameter of the 3D video before being adjusted. In theparallax parameter adjustment function p=ƒ (t, d), the parallaxparameter threshold may be a decrease function of the current degree ofeyestrain of the user. In other words, the parallax parameter thresholdof the 3D video may decrease as the current degree of eyestrain of theuser increases.

According to the visual characteristic of a human eye that the human eyefocuses when viewing an object, a processing technology of adjusting theparallax may be not only a method of reducing the mean parallax orparallax range, but also a method of ensuring a smooth change in theparallax so as to prevent the human eye from feeling uncomfortable dueto a constantly changing parallax.

The parallax adjustor 80 may also determine whether a difference betweenparallax parameters of a current frame and a previous frame of the 3Dvideo is equal to or greater than a parallax change threshold. When thedifference is equal to or greater than the parallax change threshold,the parallax adjustor 80 may adjust the parallax parameter of thecurrent frame of the 3D video such that the difference is within theparallax change threshold.

The parallax change threshold may be previously determined, ordynamically determined according to the current degree of eyestrain ofthe user. For example, the parallax change threshold may be apredetermined threshold used to measure a variation in the mean parallaxor parallax range, or may be a unique threshold used to measure avariation in a mean parallax or a parallax range that corresponds to thecurrent degree of eyestrain of the user. In detail, an appropriateparallax parameter adjustment function p′=ƒ′(t, p) may be selectedaccording to the preset condition, and the parallax parameter of thecurrent frame of the 3D video may be adjusted according to the parallaxparameter adjustment function p′=ƒ′(t, p) such that the differencebetween the parallax parameters of the current frame and the previousframe of the 3D video is within the parallax change threshold. In theparallax parameter adjustment function p′=ƒ′(t, p), p′ may refer to theparallax parameter of the 3D video after being adjusted, t may refer tothe current degree of eyestrain of the user, p may refer to the parallaxparameter of the 3D video before being adjusted. In the parallaxparameter adjustment function p′=ƒ′(t, p), the parallax parameterthreshold may be a decrease function of the current degree of eyestrainof the user. In other words, the parallax change threshold of the 3Dvideo may decrease as the current degree of eyestrain of the userincreases.

As another example, when the current degree of eyestrain of the user isequal to or greater than the eyestrain threshold, the parallax adjustor80 may adjust the parallax according to the visual characteristics of ahuman eye that the human eye focuses when viewing an object. Theparallax adjustor 80 may determine whether a difference between parallaxparameters of a current frame and a previous frame of the 3D video isequal to or greater than a parallax change threshold. When thedifference is equal to or greater than the parallax change threshold,the parallax adjustor 80 may adjust the parallax parameter of thecurrent frame of the 3D video such that the difference is within theparallax change threshold.

The device 1000 illustrated in FIG. 3 may further include an outputinterface (not shown) for outputting the 3D video to the user accordingto the adjusted parallax parameter. For example, the output interfacemay be a display device (e.g., a display).

According to the above-described method, in order to achieve a technicaleffect of 3D image display while complying with the physiologicalproperties of human eyes, the 3D display effect can be adjustedaccording to the current degree of eyestrain of the user at anappropriate moment, thereby maximizing the stereoscopic display effectof the 3D video while reducing the eyestrain of the user.

FIG. 4 illustrates a flowchart of a method of adjusting a 3D displayeffect, according to an embodiment of the present disclosure.

The method may be implemented by the device 1000 illustrated in FIG. 3,or may be completely accomplished as software through an application foradjusting a 3D display effect.

Referring to FIG. 4, in operation S410, an eye feature of a user whenthe user is viewing a 3D video may be obtained.

In detail, an image capturing device may capture a head image of theuser when the user is viewing the 3D video, and, after the head image ofthe user is obtained, a face recognition may be performed on the headimage of the user based on a computer vision library so as to parse aneye image of the user from a recognized face region. The eye feature ofthe user may be extracted from the obtained eye image of the user.

For example, at least one of a blinking frequency, an eye-closed time, achange in binocular focus points, and a binocular convergence angle maybe extracted as the eye feature from the captured eye image of the userwhen the user is viewing the 3D video.

In operation S420, a current degree of eyestrain of the user may bedetermined according to the obtained eye feature. For example, thedegree of eyestrain may be a value representing a current degree ofeyestrain of the user that is dynamically determined based on theobtained eye feature. For example, when the eye feature obtained inoperation S410 is a change in binocular focus points of the user, avalue representing the current degree of eyestrain of the user maysynthetically analyzed based on the change in the binocular focus pointsof the user.

In operation S430, a parallax parameter of the 3D video may be adjustedaccording to the current degree of eyestrain of the user. The parallaxparameter may refer to a mean parallax or parallax range of each pixelpair between a left eye image and a right eye image of the 3D video. Asdescribed above, the parallax may refer to a difference between thepositions of the same object in left and right eye images. Accordingly,in order to obtain the parallax parameter of the 3D video, an imagematching method in which a pixel corresponding to, namely, matched with,each pixel in the left eye image is detected from the right eye imageand a parallax between two matched pixels (i.e., a difference ofdisplacement) is obtained may be executed.

As the parallax of each pixel in the 3D video is obtained, a meanparallax of the 3D video or a parallax range comprised of a maximumparallax and a minimum parallax may be obtained. By adjusting the meanparallax or the parallax range, the user's eyestrain may be degraded.

In detail, the parallax parameter of the 3D video may be adjusted basedon the current degree of eyestrain of the user in an appropriate way.Examples of adjusting a display image of the 3D video will be describedin detail with reference to FIGS. 5 through 9.

FIG. 5 illustrates a flowchart of a method of adjusting a 3D displayeffect, according to another embodiment of the present disclosure.

Referring to FIG. 5, operations S510 and S520 are similar to operationS410 and S420 as illustrated in FIG. 4, and thus descriptions thereofwill be omitted herein.

In operation S530, it may be determined whether the current degree ofeyestrain of the user is equal to or greater than an eyestrainthreshold. The eyestrain threshold may be a preset critical value usedto determine whether the user experiences eye fatigue. In detail, bycomparing the current degree of eyestrain of the user with the eyestrainthreshold, it may be determined whether a 3D display effect should beadjusted.

In detail, when the current degree of eyestrain of the user is less thanthe eyestrain threshold, the parallax parameter of the 3D video may notbe adjusted. Accordingly, in operation S560, it may be determinedwhether a 3D video playback has been stopped. When the 3D video playbackhas not been stopped, the method may return to operation S510, therebycontinuing to obtain an eye feature of the user when the user is viewingthe 3D video.

On the other hand, when the current degree of eyestrain of the user isequal to or greater than the eyestrain threshold, in operation S540, itmay be determined whether the parallax parameter of the 3D video isequal to or greater than a parallax parameter threshold. For example,the parallax parameter threshold may be previously determined, ordynamically determined according to the current degree of eyestrain ofthe user. For example, the parallax parameter threshold may be apredetermined mean parallax or parallax range, or a unique meanparallax, or a parallax range that corresponds to the current degree ofeyestrain of the user.

When the parallax parameter is equal to or greater than the parallaxparameter threshold, in operation S550, the parallax parameter of the 3Dvideo may be adjusted to be within the parallax parameter threshold.

Hereafter, an example of adjusting a parallax parameter when theparallax parameter is equal to or greater than a parallax parameterthreshold will be described in conjunction with FIGS. 6A and 6B. Forexample, the parallax parameter may be particularly a parallax range ofa 3D video, and accordingly the parallax parameter threshold may referto an allowable parallax range.

In detail, referring to FIGS. 6A and 6B, a portion with a light colormay correspond to a parallax value within a parallax parameter threshold610, and a portion with a dark color may correspond to a parallax valueequal to or greater than the parallax parameter threshold 610. In FIGS.6A and 6B, “x” may refer to an illustrative parallax from amongparallaxes between matched pixels in one frame. A left-most pixel 643may be a pixel having a maximum value of a negative parallax in oneframe, and a right-most pixel 645 may be a pixel having a maximum valueof a positive parallax in the frame.

In detail, as illustrated in FIG. 6A, an interval 630 between dashedlines may refer to the parallax range of the 3D video. As illustrated inFIG. 6A, some pixels, namely, pixels 641, 643, and 645, the parallaxesof which are equal to or greater than the parallax parameter threshold,may be adjusted such that the parallaxes are less than or equal to theparallax parameter threshold.

In addition, as illustrated in FIG. 6A, in order to relieve theeyestrain of the user, the parallax range 630 may be reduced to bewithin the parallax parameter threshold 610. An appropriate parallaxparameter adjustment function p=ƒ (t, d) may be selected, and theparallax parameter of the 3D video may be adjusted (reduced) to bewithin the parallax parameter threshold according to the parallaxparameter adjustment function p=ƒ (t, d), in which p may refer to aparallax parameter of the 3D video after being adjusted, t may refer tothe current degree of eyestrain of the user, and d may refer to aparallax parameter of the 3D video before being adjusted. In theparallax parameter adjustment function p=ƒ (t, d), the parallaxparameter threshold may be a decrease function of the current degree ofeyestrain of the user. In other words, the parallax parameter thresholdof the 3D video may decrease as the current degree of eyestrain of theuser increases. Through such an adjustment, the parallax range 630 ofthe 3D video may be indicated by the dashed lines as shown in FIG. 6B.In other words, the pixels 641, 643, and 645 which were originally equalto or greater than the parallax parameter threshold may be adjusted tobe within the parallax parameter threshold, thereby reducing the degreeof eyestrain of the user.

After the parallax parameter of the 3D video is adjusted, in operationS560, it may be determined whether a 3D video playback has been stopped.When the 3D video playing has not been stopped, the method may return tooperation S510.

In addition, according to the visual characteristic of a human eye thatthe human eye focuses when viewing an object, the human eye needs tofocus when watching an object. In daily life, most of scenes are viewedby a human eye with a fixed focus. A focus point may be changed onlywhen the user wants to view an object at another distance. For example,the focus point of a human eye may be always kept on a book page whenreading the book, and the focus point of a human eye may be always kepton a display panel when watching a traditional 2D video. In this case, ahuman eye does not need to significantly and frequently adjust a focallength, so that an eyestrain may not be caused by a focus point change.However, when viewing a 3D stereoscopic video, because the scene changesconstantly, virtual subjects change at different depths, and accordinglythe focal length may change constantly. In order to see the objects inthe video clearly, an eye needs to perform a corresponding focusingadjustment. Accordingly, during watching the 3D video, such anadjustment is forced, and thus an eye muscle fatigue may be caused.

When the eye of a human cannot keep pace with the change frequency ofthe video parallax due to physical limitations, the human is unable tosee an image clearly and may feel dizzy and uncomfortable. In this case,the method of improving a viewing comfort level only by reducing theparallax parameter to some extent so as to weaken the stereoscopiceffect has a disadvantage in that a user may feel uncomfortable due tothe constantly changing parallax. For this reason, according to anembodiment of the present disclosure, the parallax parameter may beadjusted according to the visual characteristic of a human eye that thehuman eye focuses when viewing an object, so as to ensure a smoothchange in the parallax, and thus the human eye may not feeluncomfortable due to the constantly changing parallax. Hereinafter, anexample in which, when the current degree of eyestrain of the user isequal to or greater than the eyestrain threshold, the parallax parameteris adjusted according to the visual characteristic of a human eye thatthe human eye focuses when viewing things will be described in detailwith reference to FIGS. 7 through 9.

FIG. 7 illustrates a flowchart of a method of adjusting a 3D displayeffect, according to another embodiment of the present disclosure.

Referring to FIG. 7, operations S710 and S720 are similar to operationS410 and S420 as illustrated in FIG. 4, and thus descriptions thereofwill be omitted herein.

In operation S730, it may be determined whether the current degree ofeyestrain of the user is equal to or greater than an eyestrainthreshold. The eyestrain threshold may be a preset critical value usedto determine whether the user experiences eye fatigue. In detail, bycomparing the current degree of eyestrain of the user with the eyestrainthreshold, it may be determined whether a 3D display effect should beadjusted.

In detail, when the current eyestrain degree of the user is less thanthe eyestrain threshold, the parallax parameter of the 3D video may notbe adjusted. Accordingly, in operation S760, it may be determinedwhether a 3D video playback has been stopped. When the 3D video playbackhas not been stopped, the method may return to operation S710, therebycontinuing to obtain an eye feature of the user when the user is viewingthe 3D video.

On the other hand, when the current degree of eyestrain of the user isequal to or greater than the eyestrain threshold, in operation S740, itmay be determined whether a difference between parallax parameters of acurrent frame and a previous frame of the 3D video is equal to orgreater than a parallax change threshold. For example, the parallaxchange threshold may be previously determined, or dynamically determinedaccording to the current degree of eyestrain of the user. For example,the parallax change threshold may be a predetermined threshold used tomeasure a variation in the mean parallax or parallax range, or may be apredetermined unique threshold used to measure a variation in a meanparallax or parallax range corresponding to the current degree ofeyestrain of the user.

When the difference between the parallax parameters of the current frameand the previous frame of the 3D video is equal to or greater than theparallax change threshold, the parallax parameter of the current frameof the 3D video may be adjusted such that the difference is within theparallax change threshold, in operation S750.

Hereinafter, an example of adjusting a parallax parameter when theparallax parameter change between the current frame and the previousframe is equal to or greater than a parallax change threshold will beillustrated with reference to FIGS. 8A and 8B. For example, the parallaxparameter is a mean parallax of a 3D video's image frame, andaccordingly the parallax change threshold refers to an allowablevariation in the mean parallax between two adjacent frame images. FIG.8A may be a graph showing a mean parallax of each of consecutive frames.FIG. 8A may also be a graph showing a maximum value of a negativeparallax from among respective parallaxes of consecutive frames. FIG. 8Amay also be a graph showing a maximum value of a positive parallax fromamong respective parallaxes of consecutive frames. Also, FIG. 8A may bea graph showing a parallax range of each frame.

In detail, two types of parallax parameter changes, which are a positiveparallax change and a negative parallax change, may be defined. Withrespect to the positive parallax change, a value acquired by subtractingthe parallax parameter of the previous frame from the parallax parameterof the current frame may be positive. In other words, the parallaxparameter of the current frame may be larger than the parallax parameterof the previous frame. For example, a positive parallax change may beacquired by subtracting the parallax parameter of frame 4 from theparallax parameter of frame 5 in FIG. 8A. On the other hand, withrespect to the negative parallax change, a value acquired by subtractingthe parallax parameter of the previous frame from the parallax parameterof the current frame may be negative. In other words, the parallaxparameter of the current frame may be smaller than the parallaxparameter of the previous frame. For example, a negative parallax changemay be acquired by subtracting the parallax parameter of frame 7 fromthe parallax parameter of frame 8 in FIG. 8A.

In order to ensure a smooth change in the parallax parameter, regardlessof whether the current frame has a positive parallax change or anegative parallax change, when the parallax parameter change between acurrent frame and a previous frame is equal to or greater than aparallax change threshold, the parallax parameter of the current framemay be adjusted.

Referring to FIG. 8A, frames 1 to 4 form a successive negative parallaxchange with a moderate variation (i.e., the parallax change is less thanthe parallax change threshold). Therefore, it may not be required toperform a corresponding parallax parameter adjustment. However, sincethe positive parallax change acquired by subtracting the parallaxparameter of frame 4 from the parallax parameter of frame 5 is equal toor greater than the parallax change threshold, in order to relieve theeyestrain of the user, it is required to reduce the parallax parameterof frame 5 such that the difference between the parallax parameter offrame 5 and the parallax parameter of frame 4 is within the parallaxchange threshold.

An appropriate parallax parameter adjustment function p′=ƒ′(t, p) may beselected, and the parallax parameter of frame 5 of the 3D video may beadjusted according to the parallax parameter adjustment functionp′=ƒ′(t, p) such that the difference between the parallax parameters offrames 4 and 5 of the 3D video is within the parallax change threshold.In the parallax parameter adjustment function p′=ƒ′(t, p), p may referto the parallax parameter of the 3D video after being adjusted, t mayrefer to the current degree of eyestrain of the user, p may refer to theparallax parameter of the 3D video before being adjusted. In theparallax parameter adjustment function p′=ƒ′(t, p), the parallaxparameter threshold may be a decrease function of the current degree ofeyestrain of the user. In other words, the parallax change threshold ofthe 3D video may decrease as the current degree of eyestrain of the userincreases.

Through such an adjustment, the parallax parameter of frame 5 of the 3Dvideo may be reduced as shown in FIG. 8B. In other words, the differencebetween the parallax parameters of frames 4 and 5 may be adjusted to bewithin the parallax change threshold. In addition, since frames 6 and 7change relatively largely compared with the adjusted image frame (i.e.,the variations in frames 6 and 7 are equal to or greater than theparallax change threshold), the parallax parameters of frames 6 and 7may be adjusted in the same way so as to obtain the adjusted frames 6and 7 as illustrated in FIG. 8B.

On the other hand, referring to FIGS. 8A and 8B, since a differenceobtained by subtracting the adjusted parallax parameter of frame 7 fromthe parallax parameter of frame 8 is equal to or greater than theparallax change threshold, in order to relieve the eyestrain of theuser, it is required to reduce the parallax parameter of frame 8 suchthat the difference between the parallax parameter of frame 8 and theparallax parameter of frame 7 is within the parallax change threshold.Accordingly, similar to the above manner, the parallax parameter offrame 8 may be adjusted (increased) according to the parallax parameteradjustment function p′=ƒ′(t, d), so that the difference between theparallax parameter of frame 8 and the parallax parameter of frame 7 iswithin the parallax change threshold.

Moreover, since frames 9 to 11 form a successive negative parallaxchange with a relatively large variation (i.e., the parallax change isequal to or greater than the parallax change threshold), these threeframes may be adjusted in a similar way as that for frame 8 so as toobtain adjusted respective image frames as shown in FIG. 8B. As can beseen in the above manner, a smooth change in the parallax parameter canbe guaranteed, thereby reducing the degree of eyestrain of the user.

Hereinafter, in conjunction with a more specific example, a method ofadjusting a parallax parameter according to the human eye focusingcharacteristics when a scene change happens will be disclosed.

As described above, since the depths of objects in the 3D video changeconstantly, the parallax parameters change as well, and frequentlychanged focusing makes a user feel uncomfortable in his or her eyes.Such a depth change may happen in the same scene, or happen when a scenechange happens.

FIGS. 9A, 9B and 9C illustrates an example of adjusting a parallaxparameter based on a human eye focusing characteristic when changing ascene, according to an embodiment of the present disclosure. Referringto FIGS. 9A, 9B and 9C, a scene change may happen in 3D video pictures,and a round object in a picture may be replaced by a triangular object.For clarity, the same objects in left and right eye pictures arerepresented by different shades. An object with a bright color may referto a left eye picture, and an object with a dark color may refer to aright eye picture. As can be seen from FIGS. 9A and 9B, there is arelatively large positive parallax in the picture in FIG. 9A, and thereis a relatively small positive parallax in the picture in FIG. 9B. Itcan thus be seen that with respect to a current frame, a relativelylarge negative parallax change may be obtained by subtracting arelatively large positive parallax of a previous frame from a relativelysmall positive parallax of the current frame. When the negative parallaxchange is equal to or greater than the parallax change threshold, theparallax parameter needs to be adjusted.

For example, in this specific example, an adjustment may be performed byincreasing or extending the parallax parameter of the current frame. Theadjusted image frame is illustrated in FIG. 9C. As illustrated in FIG.9C, the processed frame image has a relatively large positive parallaxwith respect to FIG. 9B, and thus the adjusted positive parallax of thecurrent frame may become relatively close to the positive parallax ofthe previous frame, and a parallax parameter change in the current framemay be within the parallax change threshold.

Referring back to FIG. 7, after the parallax parameter of the 3D videois adjusted, in operation S760, it may be determined whether a 3D videoplayback has been stopped. When the 3D video playing has not beenstopped, the method may return to operation S710.

Through the above process, the parallax change that forces the eye tochange a focal length may be reduced according to a visualcharacteristic of a human eye that the human eye focuses when viewingthings. Thus, the flatness of the parallax may be ensured during aplayback process of the 3D video. Accordingly, the playback of the 3Dvideo may comply with the physiological property of human eyes to ahigher degree while guaranteeing the 3D visual effect, in order toimprove the visual comfort level of the user.

In addition, in order to achieve a better adjustment effect, the twomanners described above may be combined.

FIG. 10 illustrates a flowchart of a method of adjusting a 3D displayeffect, according to another embodiment of the present disclosure.

Referring to FIG. 10, operations S1010 and S1020 are similar tooperation S410 and S420 as illustrated in FIG. 4, and thus descriptionsthereof will be omitted herein.

In operation S1030, it may be determined whether the current degree ofeyestrain of the user is equal to or greater than an eyestrainthreshold. The eyestrain threshold may be a preset critical value usedto determine whether the user experiences eye fatigue. In detail, bycomparing the current degree of eyestrain of the user with the eyestrainthreshold, it may be determined whether a 3D display effect should beadjusted.

In detail, when the current degree of eyestrain of the user is less thanthe eyestrain threshold, the parallax parameter of the 3D video may notbe adjusted. Accordingly, in operation S1080, it may be determinedwhether a 3D video playback has been stopped. When the 3D video playbackhas not been stopped, the method may return to operation S1010, therebycontinuing to obtain an eye feature of the user when the user is viewingthe 3D video.

On the other hand, when the current degree of eyestrain of the user isequal to or greater than the eyestrain threshold, in operation S1040, itmay be determined whether the parallax parameter of the 3D video isequal to or greater than a parallax parameter threshold. For example,the parallax parameter threshold may be previously determined, ordynamically determined according to the current degree of eyestrain ofthe user. For example, the parallax parameter threshold may be apredetermined mean parallax, a predetermined parallax range, or apredetermined unique mean parallax, or may be a parallax rangecorresponding to the current degree of eyestrain of the user.

When the parallax parameter is equal to or greater than the parallaxparameter threshold, in operation S1050, the parallax parameter of the3D video may be adjusted to be within the parallax parameter threshold.

Moreover, preferably, in operation S1060, it may be determined whether adifference between parallax parameters of a current frame and a previousframe of the 3D video is equal to or greater than a parallax parameterthreshold. For example, the parallax change threshold may be previouslydetermined, or dynamically determined according to the current degree ofeyestrain of the user. For example, the parallax change threshold may bea predetermined threshold used to measure a variation in the meanparallax or parallax range, or may be a predetermined unique thresholdused to measure a variation in a mean parallax or parallax rangecorresponding to the current degree of eyestrain of the user.

When the difference between the parallax parameters of the current frameand the previous frame of the 3D video is equal to or greater than theparallax change threshold, the parallax parameter of the current frameof the 3D video may be adjusted such that the difference is within theparallax change threshold, in operation S1070.

After the parallax parameter of the 3D video is adjusted, in operationS1080, it may be determined whether a 3D video playback has beenstopped. When the 3D video playing has not been stopped, the method mayreturn to operation S1010.

As described above, in the device 1000 and the method, the 3D displayeffect can be adjusted according to the current degree of eyestrain ofthe user at an appropriate moment, thereby ensuring the stereoscopicdisplay effect of the 3D video while reducing the eyestrain of the user.Accordingly, a technical effect of 3D image display complying with thephysiological property of human eyes may be obtained.

FIG. 11 illustrates a user interface for adjusting a 3D display effect,according to an embodiment of the present disclosure.

Referring to FIG. 11, after the device 1000 automatically performs aparallax adjustment on 3D video, the device 1000 may display anotification window 1120 indicating that the parallax adjustment hasbeen completed.

The notification window 1120 may include an OK button 1122, a re-adjustbutton 1124, and a cancel button 1126.

In response to a user input of selecting the OK button 1122, the device1000 may delete the notification window. According to an embodiment, thedevice 1000 may delete the notification window when a preset time periodlapses.

In response to a user input of selecting the re-adjust button 1124, thedevice 1000 may continuously adjust the parallax of the 3D video, basedon a current parallax parameter threshold, regardless of the degree ofeyestrain of a user

In response to a user input of selecting the cancel button 1126, thedevice 1000 may return the parallax-adjusted 3D video back to theoriginal state in which the 3D video is not adjusted.

FIGS. 12 and 13 are block diagrams of devices 1000 according to someembodiments.

Referring to FIG. 12, the device 1000 may include a user input interface1100, an output interface 1200, a processor 1300, and a communicator1500. All of the components illustrated in FIG. 12 are not essentialcomponents of the device 1000. More or less components than thoseillustrated in FIG. 12 may constitute the device 1000.

For example, referring to FIG. 13, the device 1000 may further include asensing unit 1400, an audio/video (A/V) input interface 1600, and amemory 1700, in addition to the user input interface 1100, the outputinterface 1200, the processor 1300, and the communicator 1500.

A camera 1610 may be attached to the device 1000 and capture a faceimage including the eyes of a user. The camera 1610 may be attached tothe glasses (not shown) of a user for watching 3D video and may capturean eye image of the user.

The user input interface 1100 denotes means via which a user inputs datafor controlling the device 1000. For example, the user input interface1100 may be, but is not limited to, a key pad, a dome switch, a touchpad (e.g., a capacitive overlay type, a resistive overlay type, aninfrared beam type, an integral strain gauge type, a surface acousticwave type, a piezo electric type, or the like), a jog wheel, or a jogswitch.

The user input interface 1100 may receive a user input of adjusting theparallax of the 3D video.

The output interface 1200 may output an audio signal, a video signal, ora vibration signal, and may include a display 1210, an audio outputinterface 1220, and a vibration motor 1230.

The display 1210 displays information that is processed by the device1000. For example, the display 1210 may display the 3D video. Thedisplay 1210 may also display a notification window indicating that theparallax of the 3D video has been adjusted.

When the display 1210 forms a layer structure together with a touch padto construct a touch screen, the display 1210 may be used as an inputdevice as well as an output device. The display 1210 may include atleast one of a liquid crystal display (LCD), a thin filmtransistor-liquid crystal display (TFT-LCD), an organic light-emittingdiode (OLED), a flexible display, a 3D display, and an electrophoreticdisplay. According to embodiments of the device 1000, the device 1000may include at least two displays 1210. The at least two displays 1210may be disposed to face each other by using a hinge.

The audio output interface 1220 outputs audio data that is received fromthe communicator 1500 or stored in the memory 1700. The audio outputinterface 1220 may also output an audio signal (for example, a callsignal receiving sound, a message receiving sound, a notification sound)related with a function of the device 1000. The audio output interface1220 may include, for example, a speaker and a buzzer.

The vibration motor 1230 may output a vibration signal. For example, thevibration motor 1230 may output a vibration signal corresponding to anoutput of audio data or video data (for example, a call signal receivingsound or a message receiving sound). The vibration motor 1230 may alsooutput a vibration signal when a touch screen is touched.

The processor 1300 typically controls all operations of the device 1000.For example, the processor 1300 may control the user input interface1100, the output interface 1200, the sensing unit 1400, the communicator1500, the A/V input unit 1600, and the like by executing programs storedin the memory 1700.

For example, the processor 1300 may obtain an eye feature of the userfrom a captured eye image of the user, determine a current degree ofeyestrain of the user based on the obtained eye feature, and adjust theparallax of the 3D video according to the current degree of eyestrain ofthe user.

For example, the processor 1300 may adjust the parallax of the 3D videoby adjusting a change rate of a parallax between frames of the 3D video.In this case, the processor 1300 may determine whether a differencebetween parallaxes of a current frame and a previous frame of the 3Dvideo is equal to or greater than a parallax change threshold. When thedifference is equal to or greater than the parallax change threshold,the processor 1300 may adjust the parallax of the current frame of the3D video such that the difference is within the parallax changethreshold, thereby adjusting a change rate of the parallaxes between thecurrent and previous frames of the 3D video.

The processor 1300 may also determine whether the current degree ofeyestrain of the user is equal to or greater than an eyestrainthreshold. When the current degree of eyestrain of the user is equal toor greater than the eyestrain threshold, the processor 1300 may adjustthe parallax of the 3D video.

In addition, when the current degree of eyestrain of the user is equalto or greater than the eyestrain threshold, the processor 1300 maydetermine whether the parallax of the 3D video is equal to or greaterthan a parallax threshold. When the parallax is equal to or greater thanthe parallax threshold, the processor 1300 may adjust the parallax ofthe 3D video to be within the parallax threshold.

Moreover, the processor 1300 may adjust the parallax change thresholdaccording to the current degree of eyestrain of the user. Moreover, theprocessor 1300 may adjust the parallax parameter threshold according tothe current degree of eyestrain of the user.

For example, when the current degree of eyestrain of the user is large,the processor 1300 may lower the parallax change threshold and theparallax parameter threshold. The processor 1300 may adjust the parallaxof the 3D video, based on the lowered parallax change threshold and thelowered parallax parameter threshold.

The sensing unit 1400 may sense the status of the device 1000 or thestatus of the surrounding of the device 1000 and may transmitinformation corresponding to the sensed status to the processor 1300.

The sensing unit 1400 may include, but is not limited thereto, at leastone selected from a magnetic sensor 1410, an acceleration sensor 1420, atemperature/humidity sensor 1430, an infrared sensor 1440, a gyroscopesensor 1450, a position sensor (e.g., a global positioning system (GPS))1460, a pressure sensor 1470, a proximity sensor 1480, and an RGB sensor1490 (i.e., an illuminance sensor). Functions of most of the sensorswould be instinctively understood by one of ordinary skill in the art inview of their names and thus detailed descriptions thereof will beomitted herein.

The communicator 1500 may include at least one component that enablesthe device 1000 to perform data communication with and another device(not shown) or a server (not shown). For example, the communicator 1500may include a short-range wireless communication unit 1510, the mobilecommunication unit 1520, and a broadcasting reception unit 1530.

The short-range wireless communication unit 1510 may include, but is notlimited to, a Bluetooth communicator, a BLE communicator, an NFC unit, awireless local area network (WLAN) (e.g., Wi-Fi) communicator, a ZigBeecommunicator, an infrared Data Association (IrDA) communicator, a WFDcommunicator, an UWB communicator, an Ant+ communicator, and the like.

The mobile communication unit 1520 may exchange a wireless signal withat least one selected from a base station, an external terminal, and aserver on a mobile communication network. Here, examples of the wirelesssignal may include a voice call signal, a video call signal, and varioustypes of data according to text/multimedia messages transmission.

The broadcasting reception unit 1530 receives a broadcasting signaland/or broadcasting-related information from an external source via abroadcasting channel. The broadcasting channel may be a satellitechannel, a ground wave channel, or the like. According to embodiments,the device 1000 may not include the broadcasting reception unit 1530.

The A/V input interface 1600 is to input an audio signal or a videosignal, and may include the camera 1610 and a microphone 1620. Thecamera 1610 may acquire an image frame, such as a still image or amoving picture, via an image sensor in a video call mode or aphotography mode. An image captured via the image sensor may beprocessed by the processor 1300 or a separate image processor (notshown).

The image frame obtained by the camera 1610 may be stored in the memory1700 or transmitted to the outside via the communicator 1500. At leasttwo cameras 1610 may be included according to embodiments of thestructure of a terminal.

The microphone 1620 receives an external audio signal and converts theexternal audio signal into electrical audio data. For example, themicrophone 1620 may receive an audio signal from an external device or aspeaking person. The microphone 1620 may use various noise removalalgorithms in order to remove noise that is generated while receivingthe external audio signal.

The memory 1700 may store a program used by the processor 1300 toperform processing and control, and may also store data that is input toor output from the device 1000.

The memory 1700 may include at least one type of storage medium selectedfrom among a flash memory type, a hard disk type, a multimedia cardmicro type, a card type memory (for example, a secure digital (SD) orextreme digital (XD) memory), a random access memory (RAM), a staticrandom access memory (SRAM), a read-only memory (ROM), an electricallyerasable programmable ROM (EEPROM), a programmable ROM (PROM), magneticmemory, a magnetic disk, and an optical disk.

The programs stored in the memory 1700 may be classified into aplurality of modules according to their functions, for example, a UImodule 1710, a touch screen module 1720, and a notification module 1730.

The UI module 1710 may provide a UI, graphical user interface (GUI), orthe like that is specialized for each application and interoperates withthe device 1000. The touch screen module 1720 may detect a touch gestureon a touch screen of a user and transmit information regarding the touchgesture to the processor 1300. The touch screen module 1720 according toan embodiment may recognize and analyze a touch code. The touch screenmodule 1720 may be configured by separate hardware including acontroller.

In order to detect the actual touch or the proximate touch on the touchpad, the touch screen may internally or externally have various sensors.An example of a sensor used to detect a real touch or a proximity touchon the touch screen is a tactile sensor. The tactile sensor denotes asensor that detects a touch by a specific object to a degree to which ahuman feels or more. The tactile sensor may detect various types ofinformation, such as the roughness of a touched surface, the hardness ofthe touching object, and the temperature of a touched point.

Another example of a sensor used to detect the real touch or theproximity touch on the touch screen is a proximity sensor.

The proximity sensor senses the existence of an object that approachesthe predetermined sensing surface or an object that exists nearby,without mechanical contact, by using an electromagnetic force orinfrared rays. Examples of the proximity sensor include atransmission-type photoelectric sensor, a direct reflection-typephotoelectric sensor, a mirror reflection-type photoelectric sensor, ahigh frequency oscillation-type proximity sensor, a capacity-typeproximity sensor, a magnetic proximity sensor, and an infrared-typeproximity sensor. Examples of the touch gesture of the user may includetap, touch and hold, double tap, drag, panning, flick, drag and drop,swipe, and the like.

The notification module 1730 may generate a signal for notifying that anevent has been generated in the device 1000. Examples of the eventgenerated in the electronic apparatus 1000 may include call signalreceiving, message receiving, a key signal input, schedule notification,and the like. The notification module 1730 may output a notificationsignal in the form of a video signal via the display 1210, in the formof an audio signal via the audio output interface 1220, or in the formof a vibration signal via the vibration motor 1230.

The embodiment of the present invention can be embodied in a storagemedium including instruction codes executable by a computer such as aprogram module executed by the computer. A computer readable medium canbe any available medium which can be accessed by the computer andincludes all volatile/non-volatile and removable/non-removable media.Further, the computer readable medium may include all computer storageand communication media. The computer storage medium includes allvolatile/non-volatile and removable/non-removable media embodied by acertain method or technology for storing information such as computerreadable instruction code, a data structure, a program module or otherdata. The communication medium typically includes the computer readableinstruction code, the data structure, the program module, or other dataof a modulated data signal such as a carrier wave, or other transmissionmechanism, and includes any information transmission medium.

While one or more embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims.

Although general terms widely used at present were selected fordescribing the present invention in consideration of the functionsthereof, these general terms may vary according to intentions of one ofordinary skill in the art, case precedents, the advent of newtechnologies, and the like. Terms arbitrarily selected by the applicantof the present invention may also be used in a specific case. In thiscase, their meanings need to be given in the detailed description of theinvention. Hence, the terms must be defined based on their meanings andthe contents of the entire specification, not by simply stating theterms.

The terms “comprises” and/or “comprising” or “includes” and/or“including” when used in this specification, specify the presence ofstated elements, but do not preclude the presence or addition of one ormore other elements. The terms “ . . . unit” and “ . . . module” whenused in this specification refers to a unit in which at least onefunction or In operation is performed, and may be implemented ashardware, software, or a combination of hardware and software.

Embodiments of the present invention are described in detail herein withreference to the accompanying drawings so that this disclosure may beeasily performed by one of ordinary skill in the art to which thepresent invention pertain. The present disclosure may, however, beembodied in many different forms and should not be construed as beinglimited to the embodiments set forth herein. In the drawings, partsirrelevant to the description are omitted for simplicity of explanation,and like numbers refer to like elements throughout.

1. A device comprising: an image capturing unit configured to capture animage of eyes of a user who is watching three-dimensional (3D) video;and a processor configured to obtain an eye feature of the user from thecaptured image of the eyes of the user, determine a degree of eyestraindegree of the user based on the obtained eye feature, and adjust aparallax of the 3D video according to the degree of eyestrain of theuser.
 2. The device of claim 1, wherein the processor adjusts theparallax of the 3D video by adjusting at least one of a mean parallaxbetween a left eye image and a right eye image of the 3D video, amaximum value of a negative parallax between the left and right eyeimages, a maximum value of a positive parallax between the left andright eye images, and a parallax range that is a difference between themaximum value of the negative parallax and the maximum value of thepositive parallax.
 3. The device of claim 1, wherein the eye feature ofthe user comprises at least one of a blinking frequency, an eye-closedtime, a change in binocular focus points, and a binocular convergenceangle.
 4. The device of claim 1, wherein, when the determined degree ofeyestrain of the user is equal to or greater than a first threshold, theprocessor adjusts the parallax of the 3D video.
 5. The device of claim1, wherein the processor determines whether the parallax of the 3D videois equal to or greater than a second threshold, and, when the parallaxof the 3D video is equal to or greater than the second threshold, theprocessor adjusts the parallax of the 3D video to be less than thesecond threshold.
 6. The device of claim 1, wherein the processoradjusts the parallax of the 3D video by adjusting a change rate of aparallax between frames of the 3D video.
 7. The device of claim 6,wherein the processor determines a difference between parallaxes of ann-th frame and an (n−1)th frame of the 3D video, and, when thedifference between the parallaxes is equal to or greater than a thirdthreshold, the processor adjusts the parallax of the n-th frame suchthat the difference between the parallaxes is less than the thirdthreshold, to thereby adjust the change rate of the parallax between theframes of the 3D video.
 8. The device of claim 7, wherein the processorincreases the parallax of the n-th frame such that the differencebetween the parallaxes is less than the third threshold, to therebyadjust the change rate of the parallax between the frames of the 3Dvideo.
 9. The device of claim 1, further comprising an output interface,wherein the processor controls the output interface to output, to theuser, a parallax-adjusted 3D video obtained by adjusting the parallax ofthe 3D video.
 10. The device of claim 9, wherein the device displays, onthe output interface, a notification window indicating that the parallaxof the 3D video has been adjusted.
 11. A method of adjusting athree-dimensional (3D) display effect, the method comprising: capturingan image of eyes of a user who is watching 3D video; obtaining an eyefeature of the user from an image of the captured image of the eyes ofthe user; determining a degree of eyestrain of the user, based on theobtained eye feature; and adjusting a parallax of the 3D video accordingto the degree of eyestrain of the user.
 12. The method of claim 11,wherein the adjusting of the parallax of the 3D video according to thedegree of eyestrain of the user comprises adjusting at least one of amean parallax between a left eye image and a right eye image of the 3Dvideo, a maximum value of a negative parallax between the left and righteye images, a maximum value of a positive parallax between the left andright eye images, and a parallax range that is a difference between themaximum value of the negative parallax and the maximum value of thepositive parallax.
 13. The method of claim 11, wherein the eye featureof the user comprises at least one of a blinking frequency, aneye-closed time, a change in binocular focus points, and a binocularconvergence angle.
 14. The method of claim 11, wherein the adjusting ofthe parallax of the 3D video according to the degree of eyestrain of theuser comprises, when the determined degree of eyestrain of the user isequal to or greater than a first threshold, adjusting the parallax ofthe 3D video.
 15. The method of claim 11, wherein the adjusting of theparallax of the 3D video according to the degree of eyestrain of theuser comprises determining whether the parallax of the 3D video is equalto or greater than a second threshold, and, when the parallax of the 3Dvideo is equal to or greater than the second threshold, adjusting theparallax of the 3D video to be less than the second threshold.
 16. Themethod of claim 11, wherein the adjusting of the parallax of the 3Dvideo according to the degree of eyestrain of the user comprisesadjusting the parallax of the 3D video by adjusting a change rate of aparallax between frames of the 3D video.
 17. The method of claim 16,wherein the adjusting of the parallax of the 3D video by adjusting thechange rate of the parallax between frames of the 3D video comprisesdetermining a difference between parallaxes of an n-th frame and an(n−1)th frame of the 3D video, and, when the difference between theparallaxes is equal to or greater than a third threshold, adjusting theparallax of the n-th frame such that the difference between theparallaxes is less than the third threshold, to thereby adjust thechange rate of the parallax between the frames of the 3D video.
 18. Themethod of claim 17, wherein the adjusting of the parallax of the n-thframe such that the difference between the parallaxes is less than thethird threshold comprises increasing the parallax of the n-th frame suchthat the difference between the parallaxes is less than the thirdthreshold, to thereby adjust the change rate of the parallax between theframes of the 3D video.
 19. The method of claim 11, further comprisingoutputting, to the user, a parallax-adjusted 3D video obtained byadjusting the parallax of the 3D video.
 20. The method of claim 19,further comprising displaying a notification window indicating that theparallax of the 3D video has been adjusted.